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mregoan(at)hispeed.ch
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 Posted: Sun Feb 28, 2010 12:47 pm Post subject: Water ballast tank |
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Folks,
I’m about to start riveting the VS and want to put my mind to rest about W&B issues before doing so. My concern is trying to optimize the W&B so that the use of ballast, if at all required, is as easy (and light) as possible.
I anticipate running into a rear CG problem with 4 passengers and baggage. I'm assuming some moderate soundproofing and interior (circa 20lbs) and the MT 3-blade prop, which both move CG rearwards. My "solution" is to move the battery forwards to the firewall. This avoids having a rear CG problem in all practical circumstances, reduces cable weight and voltage drop during starting, but increases the issue with the inadequate elevator trim when flying solo or dual. To solve that, I proposed putting a water ballast tank near the tail, instead of using the traditional shot bags used by Van's in the demonstrator. This minimizes the weight required, and would allow dumping and refilling the ballast anywhere, anytime.
Vans have helped me in so much as confirming the following:
<![if !supportLists]>1. <![endif]>If loaded with a CG at front limit of 15% (ie. solo, no ballast), the plane can be landed OK with half flaps or a touch of power in the flare.
<![if !supportLists]>2. <![endif]>A comfortable CG location for landing is around 18% or rearward.
<![if !supportLists]>3. <![endif]>Structurally, putting a water ballast tank in the tail is "probably OK". The VS appeared to be the preferred location rather than the rear fuselage. The space between the lower and middle inspar ribs is the perfect volume.
<![if !supportLists]>4. <![endif]>Nothing disastrous will happen with the CG at 32%.
So now I'm considering 2 options:
Option 1: Move the battery forwards, add the water ballast tank (or use a lot of ballast in the baggage bay). No problem ever with the rear CG, but ballast is a must if flying solo, to keep behind 15%.
Option 2: Leave the battery where it is. Accept CG back to 32%. Never need to use ballast.
I would appreciate any feedback from those who are flying regularly near gross with passengers or who have the experience from flight testing. Does the plane really fly OK with a CG location slightly rear of limits?
Also, if anyone can help me find the summary weight and balance table of all the finished -10's I would be grateful. The rvproject link mentioned in some messages on the forum doesn't seem to work when I try.
Fly safe!
Gordon Anderson
Switzerland
VS primed (DuPont 825R/XB383  )
[quote][b]
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Kelly McMullen
Joined: 16 Apr 2008
Posts: 1188
Location: Sun Lakes AZ
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| Posted: Sun Feb 28, 2010 1:28 pm Post subject: Water ballast tank |
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Why would you want to build in a tank? If you are full you won't need
ballast for sure. If you are solo, a collapsible 5 gal jug should be
plenty, that could easily be carried into FBO and filled, as opposed
to needing a hose or a container to get water to plane. Jug could be
easily secured in baggage. I'll let the flying folks comment on W&B,
but I sure wouldn't be adding complexity to your build at this stage,
and not in the VS. Better to worry about what primer to use, or not.
))
On Sun, Feb 28, 2010 at 1:44 PM, Gordon Anderson <mregoan(at)hispeed.ch> wrote:
| Quote: | Folks,
I’m about to start riveting the VS and want to put my mind to rest about W&B
issues before doing so. My concern is trying to optimize the W&B so that the
use of ballast, if at all required, is as easy (and light) as possible.
I anticipate running into a rear CG problem with 4 passengers and baggage.
I'm assuming some moderate soundproofing and interior (circa 20lbs) and the
MT 3-blade prop, which both move CG rearwards. My "solution" is to move the
battery forwards to the firewall. This avoids having a rear CG problem in
all practical circumstances, reduces cable weight and voltage drop during
starting, but increases the issue with the inadequate elevator trim when
flying solo or dual. To solve that, I proposed putting a water ballast
tank near the tail, instead of using the traditional shot bags used by Van's
in the demonstrator. This minimizes the weight required, and would allow
dumping and refilling the ballast anywhere, anytime.
Vans have helped me in so much as confirming the following:
1. If loaded with a CG at front limit of 15% (ie. solo, no ballast), the
plane can be landed OK with half flaps or a touch of power in the flare.
2. A comfortable CG location for landing is around 18% or rearward.
3. Structurally, putting a water ballast tank in the tail is "probably OK".
The VS appeared to be the preferred location rather than the rear fuselage.
The space between the lower and middle inspar ribs is the perfect volume.
4. Nothing disastrous will happen with the CG at 32%.
So now I'm considering 2 options:
Option 1: Move the battery forwards, add the water ballast tank (or use a
lot of ballast in the baggage bay). No problem ever with the rear CG, but
ballast is a must if flying solo, to keep behind 15%.
Option 2: Leave the battery where it is. Accept CG back to 32%. Never need
to use ballast.
I would appreciate any feedback from those who are flying regularly near
gross with passengers or who have the experience from flight testing. Does
the plane really fly OK with a CG location slightly rear of limits?
Also, if anyone can help me find the summary weight and balance table of all
the finished -10's I would be grateful. The rvproject link mentioned in some
messages on the forum doesn't seem to work when I try.
Fly safe!
Gordon Anderson
Switzerland
VS primed (DuPont 825R/XB383 )
|
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_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor
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dlm46007(at)cox.net
Guest
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| Posted: Sun Feb 28, 2010 1:28 pm Post subject: Water ballast tank |
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Have you accounted for the 25 pound tool and spares box that is carried with each experimental. Unless you carry all the service manuals (or the tools) how are you going to maintain/fix the aircraft away from home base. Many FBOs won't touch them with out manufacturers continued airworthiness documents (insurance reasons). One must be prepared to maintain it and have a few spare parts available in the tool box; i,e, serviceable spark plug, master contactor, starter relay, spare cowl pin material, etc
From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Gordon Anderson
Sent: Sunday, February 28, 2010 1:45 PM
To: rv10-list(at)matronics.com
Subject: Water ballast tank
Folks,
I’m about to start riveting the VS and want to put my mind to rest about W&B issues before doing so. My concern is trying to optimize the W&B so that the use of ballast, if at all required, is as easy (and light) as possible.
I anticipate running into a rear CG problem with 4 passengers and baggage. I'm assuming some moderate soundproofing and interior (circa 20lbs) and the MT 3-blade prop, which both move CG rearwards. My "solution" is to move the battery forwards to the firewall. This avoids having a rear CG problem in all practical circumstances, reduces cable weight and voltage drop during starting, but increases the issue with the inadequate elevator trim when flying solo or dual. To solve that, I proposed putting a water ballast tank near the tail, instead of using the traditional shot bags used by Van's in the demonstrator. This minimizes the weight required, and would allow dumping and refilling the ballast anywhere, anytime.
Vans have helped me in so much as confirming the following:
<![if !supportLists]>1. <![endif]>If loaded with a CG at front limit of 15% (ie. solo, no ballast), the plane can be landed OK with half flaps or a touch of power in the flare.
<![if !supportLists]>2. <![endif]>A comfortable CG location for landing is around 18% or rearward.
<![if !supportLists]>3. <![endif]>Structurally, putting a water ballast tank in the tail is "probably OK". The VS appeared to be the preferred location rather than the rear fuselage. The space between the lower and middle inspar ribs is the perfect volume.
<![if !supportLists]>4. <![endif]>Nothing disastrous will happen with the CG at 32%.
So now I'm considering 2 options:
Option 1: Move the battery forwards, add the water ballast tank (or use a lot of ballast in the baggage bay). No problem ever with the rear CG, but ballast is a must if flying solo, to keep behind 15%.
Option 2: Leave the battery where it is. Accept CG back to 32%. Never need to use ballast.
I would appreciate any feedback from those who are flying regularly near gross with passengers or who have the experience from flight testing. Does the plane really fly OK with a CG location slightly rear of limits?
Also, if anyone can help me find the summary weight and balance table of all the finished -10's I would be grateful. The rvproject link mentioned in some messages on the forum doesn't seem to work when I try.
Fly safe!
Gordon Anderson
Switzerland
VS primed (DuPont 825R/XB383 )
[quote]
href="http://www.matronics.com/Navigator?RV10-List">http://www.matronics.com/Navigator?RV10-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
[b]
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Jim Berry
Joined: 10 Jan 2006
Posts: 237
Location: Denver
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| Posted: Sun Feb 28, 2010 1:49 pm Post subject: Re: Water ballast tank |
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Have you considered what happens if the water in your VS tank freezes?
Jim Berry
40482
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Tim Olson
Joined: 25 Jan 2007
Posts: 2879
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| Posted: Sun Feb 28, 2010 2:08 pm Post subject: Water ballast tank |
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Definitely way too early to worry about it...and I don't think the VS
is a good spot for ballast. Sounds like you're way overthinking
things. Time to find a flying 10 and go for a ride.
Tim
On Feb 28, 2010, at 3:20 PM, Kelly McMullen <apilot2(at)gmail.com> wrote:
| Quote: |
Why would you want to build in a tank? If you are full you won't need
ballast for sure. If you are solo, a collapsible 5 gal jug should be
plenty, that could easily be carried into FBO and filled, as opposed
to needing a hose or a container to get water to plane. Jug could be
easily secured in baggage. I'll let the flying folks comment on W&B,
but I sure wouldn't be adding complexity to your build at this stage,
and not in the VS. Better to worry about what primer to use, or not.
))
On Sun, Feb 28, 2010 at 1:44 PM, Gordon Anderson
<mregoan(at)hispeed.ch> wrote:
> Folks,
>
> I’m about to start riveting the VS and want to put my mind to rest
> about W&B
> issues before doing so. My concern is trying to optimize the W&B so
> that the
> use of ballast, if at all required, is as easy (and light) as
> possible.
>
> I anticipate running into a rear CG problem with 4 passengers and
> baggage.
> I'm assuming some moderate soundproofing and interior (circa
> 20lbs) and the
> MT 3-blade prop, which both move CG rearwards. My "solution" is to
> move the
> battery forwards to the firewall. This avoids having a rear CG
> problem in
> all practical circumstances, reduces cable weight and voltage drop
> during
> starting, but increases the issue with the inadequate elevator trim
> when
> flying solo or dual. To solve that, I proposed putting a water
> ballast
> tank near the tail, instead of using the traditional shot bags used
> by Van's
> in the demonstrator. This minimizes the weight required, and would
> allow
> dumping and refilling the ballast anywhere, anytime.
>
> Vans have helped me in so much as confirming the following:
>
> 1. If loaded with a CG at front limit of 15% (ie. solo, no
> ballast), the
> plane can be landed OK with half flaps or a touch of power in the
> flare.
>
> 2. A comfortable CG location for landing is around 18% or rearward.
>
> 3. Structurally, putting a water ballast tank in the tail is
> "probably OK".
> The VS appeared to be the preferred location rather than the rear
> fuselage.
> The space between the lower and middle inspar ribs is the perfect
> volume.
>
> 4. Nothing disastrous will happen with the CG at 32%.
>
> So now I'm considering 2 options:
>
> Option 1: Move the battery forwards, add the water ballast tank (or
> use a
> lot of ballast in the baggage bay). No problem ever with the rear
> CG, but
> ballast is a must if flying solo, to keep behind 15%.
>
> Option 2: Leave the battery where it is. Accept CG back to 32%.
> Never need
> to use ballast.
>
> I would appreciate any feedback from those who are flying regularly
> near
> gross with passengers or who have the experience from flight
> testing. Does
> the plane really fly OK with a CG location slightly rear of limits?
>
> Also, if anyone can help me find the summary weight and balance
> table of all
> the finished -10's I would be grateful. The rvproject link
> mentioned in some
> messages on the forum doesn't seem to work when I try.
>
> Fly safe!
>
> Gordon Anderson
>
> Switzerland
>
> VS primed (DuPont 825R/XB383 )
>
|
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http://www.matronics.com/Navigator?RV10-List |
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MauleDriver(at)nc.rr.com
Guest
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| Posted: Sun Feb 28, 2010 3:55 pm Post subject: Water ballast tank |
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You must be a glider guy... I liked the tail ballast in my last ship
too. And the VS is a good place.
But with over 100 flying examples and little noise about ballast issues,
there would seem to be better places to spend your efforts. Doors,
rudder trim, primer selection - they all cry for improvement.
Seriously, the scenarios you describe below suggest you would be
creating an operational issue rather than solving one (e.g. ballast must
be in place for solo flight means checking it and no leaks can be
tolerated).
Bill "really wanting to fly this thing" Watson
do not archive
Gordon Anderson wrote:
| Quote: |
Folks,
I’m about to start riveting the VS and want to put my mind to rest
about W&B issues before doing so. My concern is trying to optimize the
W&B so that the use of ballast, if at all required, is as easy (and
light) as possible.
I anticipate running into a rear CG problem with 4 passengers and
baggage. I'm assuming some moderate soundproofing and interior (circa
20lbs) and the MT 3-blade prop, which both move CG rearwards. My
"solution" is to move the battery forwards to the firewall. This
avoids having a rear CG problem in all practical circumstances,
reduces cable weight and voltage drop during starting, but increases
the issue with the inadequate elevator trim when flying solo or dual.
To solve that, I proposed putting a water ballast tank near the tail,
instead of using the traditional shot bags used by Van's in the
demonstrator. This minimizes the weight required, and would allow
dumping and refilling the ballast anywhere, anytime.
Vans have helped me in so much as confirming the following:
1. If loaded with a CG at front limit of 15% (ie. solo, no ballast),
the plane can be landed OK with half flaps or a touch of power in the
flare.
2. A comfortable CG location for landing is around 18% or rearward.
3. Structurally, putting a water ballast tank in the tail is "probably
OK". The VS appeared to be the preferred location rather than the rear
fuselage. The space between the lower and middle inspar ribs is the
perfect volume.
4. Nothing disastrous will happen with the CG at 32%.
So now I'm considering 2 options:
Option 1: Move the battery forwards, add the water ballast tank (or
use a lot of ballast in the baggage bay). No problem ever with the
rear CG, but ballast is a must if flying solo, to keep behind 15%.
Option 2: Leave the battery where it is. Accept CG back to 32%. Never
need to use ballast.
I would appreciate any feedback from those who are flying regularly
near gross with passengers or who have the experience from flight
testing. Does the plane really fly OK with a CG location slightly rear
of limits?
Also, if anyone can help me find the summary weight and balance table
of all the finished -10's I would be grateful. The rvproject link
mentioned in some messages on the forum doesn't seem to work when I try.
Fly safe!
Gordon Anderson
Switzerland
VS primed (DuPont 825R/XB383 )
*
*
|
| | - The Matronics RV10-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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rene(at)felker.com
Guest
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| Posted: Sun Feb 28, 2010 4:06 pm Post subject: Water ballast tank |
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I have an AFT CG (empty) and will be ADDING a battery to the fire wall in order to provide more backup power and move the CG forward. I also tested the airplane with the CG outside the aft CG limit and did not find any problems. I loaded the airplane up to gross weight (2800) for me, using nominal (for me) pilot and Co-pilot weights, loaded some weight in the baggage compartment and then filled up the back seats. Until I got to 2785 (if I remember right). That put the CG outside the envelope and became worse as fuel burned off. I tested the airplane in that config, again no handling problems. I did get a better break in the stalls, but that is normal as the CG moves aft. I also did my service ceiling testing in that config. (20,100).
I also flew the Vans Demonstrator for my transition training…….
I am with Tim, you are way early in the process to be thinking about a permanent mod. I think you are taking the right step first by asking the flyers…..
In my early days on the list, the concern was about the forward CG…..so I made some decisions during my build to move the CG aft….ELT location…..O2 location……Strobe Power supply…..bigger battery… things I would do a little different if I built another RV-10.
I like the way the airplane handles with the CG in the aft 25% of the envelope, BUT I think it handles great on the very front of the forward CG (Vans Demo). Everything you add (except oil) when flying is aft of the forward CG limit. And, you can always add temp ballast to the baggage compartment if you want to move the CG back.
Just my opinion…..
So…..for this annual (my second one), I am putting a 680 on the firewall along with an additional contactor, mounting box, etc I will be adding 17 lbs or so. I am also putting in the Safety Trim system and an avionics cooling fan (for DVD player…..quits during summer after running for 2 hours or more). Along with a little more interior work, I am hoping I will move the CG forward a little. As long as the 680 works well for the next year, I will then replace the 925 I have in back with a 680.
If all of that does not move my CG forward enough, I will move the ELT up next. A little extra weight in the tail can really move the CG Aft…….
Rene'
801-721-6080
From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Gordon Anderson
Sent: Sunday, February 28, 2010 1:45 PM
To: rv10-list(at)matronics.com
Subject: Water ballast tank
Folks,
I’m about to start riveting the VS and want to put my mind to rest about W&B issues before doing so. My concern is trying to optimize the W&B so that the use of ballast, if at all required, is as easy (and light) as possible.
I anticipate running into a rear CG problem with 4 passengers and baggage. I'm assuming some moderate soundproofing and interior (circa 20lbs) and the MT 3-blade prop, which both move CG rearwards. My "solution" is to move the battery forwards to the firewall. This avoids having a rear CG problem in all practical circumstances, reduces cable weight and voltage drop during starting, but increases the issue with the inadequate elevator trim when flying solo or dual. To solve that, I proposed putting a water ballast tank near the tail, instead of using the traditional shot bags used by Van's in the demonstrator. This minimizes the weight required, and would allow dumping and refilling the ballast anywhere, anytime.
Vans have helped me in so much as confirming the following:
<![if !supportLists]>1. <![endif]>If loaded with a CG at front limit of 15% (ie. solo, no ballast), the plane can be landed OK with half flaps or a touch of power in the flare.
<![if !supportLists]>2. <![endif]>A comfortable CG location for landing is around 18% or rearward.
<![if !supportLists]>3. <![endif]>Structurally, putting a water ballast tank in the tail is "probably OK". The VS appeared to be the preferred location rather than the rear fuselage. The space between the lower and middle inspar ribs is the perfect volume.
<![if !supportLists]>4. <![endif]>Nothing disastrous will happen with the CG at 32%.
So now I'm considering 2 options:
Option 1: Move the battery forwards, add the water ballast tank (or use a lot of ballast in the baggage bay). No problem ever with the rear CG, but ballast is a must if flying solo, to keep behind 15%.
Option 2: Leave the battery where it is. Accept CG back to 32%. Never need to use ballast.
I would appreciate any feedback from those who are flying regularly near gross with passengers or who have the experience from flight testing. Does the plane really fly OK with a CG location slightly rear of limits?
Also, if anyone can help me find the summary weight and balance table of all the finished -10's I would be grateful. The rvproject link mentioned in some messages on the forum doesn't seem to work when I try.
Fly safe!
Gordon Anderson
Switzerland
VS primed (DuPont 825R/XB383 )
| Quote: | | http://www.matronics.com/Navigator?RV10-List |
01234567
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